If you want to rotate an object by (45,30,20) degrees, what do you need to do?

Question

When you need to rotate an object by(45,30,20) degrees for respective axis, X,Y,Z

Is it right to first do the following on every coordinate:

x' = x
y' = y cos(45) - z sin(45)
z' = y sin (45) + z cos(45)

Then do the following for each coordinate:
x' = x cos(30) + z sin(30)
y' = y
z' = -x sin(30) + z cos (30)

After that we do the following on each coordinate:
x' = x cos(20) - y sin(20)
y'= x sin(20) + y cos(20)
z' = z

I don't know what to do. Please help.
Thank you very much.

Answer 1

No, do Z then Y and then X